CN115047599B - Small infrared thermal imaging short-focus lens - Google Patents
Small infrared thermal imaging short-focus lens Download PDFInfo
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- CN115047599B CN115047599B CN202210971284.3A CN202210971284A CN115047599B CN 115047599 B CN115047599 B CN 115047599B CN 202210971284 A CN202210971284 A CN 202210971284A CN 115047599 B CN115047599 B CN 115047599B
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
- G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
- G02B13/004—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having four lenses
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/008—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras designed for infrared light
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Abstract
The invention discloses a small infrared thermal imaging short-focus lens, which comprises a lens barrel, an image side face of a photosensitive element, a first lens, a second lens, a third lens and a fourth lens, wherein the image side face of the photosensitive element is arranged on one side of the image side face of the fourth lens; the small infrared thermal imaging lens with the total lens length TTL being less than or equal to 13.6mm, the focal length EFL being less than or equal to 7.2mm and the full FOV being less than or equal to 52.5 degrees has the advantages of good imaging quality, small and light structure, low cost and wide application range, improves the core competitiveness of related products, and improves the user experience.
Description
Technical Field
The invention relates to the technical field of electronic camera lenses, in particular to a small infrared thermal imaging short-focus lens.
Background
With the rapid and continuous development of infrared thermal imaging, the infrared thermal imaging system is more and more widely applied, for example, in the field of nondestructive testing, a machine is shot by an infrared thermal imaging instrument to search hot spots of machine equipment; or shooting a house to search a heat loss point of the house; in the medical field, doctors can diagnose diseases through the temperature change of the body surface of a human body, such as early-stage breast cancer screening; in the crowded places of personnel such as station, market, the individual that generates heat can be selected fast to the infrared thermal imager. The conventional infrared thermal imaging lens has the defects of high price, large size, large influence of temperature environment and low imaging performance stability, so that the application range of an infrared thermal imager is limited. Therefore, the development of a low-cost miniaturized infrared thermal imaging lens is urgently needed.
Disclosure of Invention
The invention aims to provide a small infrared thermal imaging short-focus lens.
In order to achieve the purpose, the invention is implemented according to the following technical scheme:
the invention comprises a lens cone, an image side surface of a photosensitive element, a first lens, a second lens, a third lens and a fourth lens, wherein the image side surface of the photosensitive element is arranged on one side of the image side surface of the lens cone;
the total lens length from the lens barrel to the image side surface of the photosensitive element is TTL (transistor-transistor logic) less than or equal to 13.6mm, the focal length EFL is less than or equal to 7.2mm, and the total FOV is not less than 52.5 degrees.
Further, an IR filter is arranged on the image side surface of the fourth lens and fixedly arranged in the lens barrel.
Preferably, the thickness of the air gap between the first lens and the second lens is 1.41mm; the thickness of the air gap between the second lens and the third lens is 0.45mm; the air gap thickness between the third lens and the fourth lens is 0.13mm; the thickness of the air gap between the lens four and the IR filter is 1.35mm; the air gap between the IR filter and the image side of the photosensitive element is 1.45mm.
Preferably, the first lens outer diameter dimension D1= phi 8.8mm, the second lens outer diameter dimension D2= phi 9.0mm, and the third lens outer diameter dimension D3= phi 9.6mm; the four outer diameter dimension of the lens D4= phi 10.0mm.
Preferably, the first lens thickness CT1=1.20mm, the second lens thickness CT2=1.00mm, the third lens thickness CT3=3.55mm, the fourth lens thickness CT4=0.80mm, and the IR filter thickness dimension is 0.70mm.
Preferably, the thickness dimension of one side of the lens ET1=1.570mm, the thickness dimension of the two sides of the lens ET2=1.800mm, the thickness dimension of the three sides of the lens ET3=1.700mm, and the thickness dimension of the four sides of the lens ET4=1.310mm.
Preferably, the radius of curvature of the object side surface of the lens is 4.0mm, the aspheric diameter phi of the object side surface is 3.21mm, the radius of curvature of the image side surface is 21.5mm, and the aspheric diameter phi of the image side surface is 3.47mm; the radius of curvature of the object side surface of the second lens is-18.4 mm, the diameter of the aspheric surface of the object side surface is phi 3.66mm, the radius of curvature of the image side surface is 6.2mm, and the diameter of the aspheric surface of the image side surface is phi 5.59mm; the radius of curvature of the object side surface of the lens is minus 27.5mm, the diameter of the aspheric surface of the object side surface is phi 5.84mm, the radius of curvature of the image side surface is minus 1.8mm, and the diameter of the aspheric surface of the image side surface is phi 6.84mm; the radius of curvature of the four object side surfaces of the lens is 2.7mm, the diameter phi of the aspheric surface of the object side surface is 7.99mm, the radius of curvature of the image side surface is 1.35mm, and the diameter phi of the aspheric surface of the image side surface is 8.04mm.
Preferably, the diameter of the light passing hole of the diaphragm is 2.85mm.
Preferably, the first lens, the second lens, the third lens and the fourth lens are all made of plastic materials.
Preferably, the refractive index Nd =1.54 and Abbe number Vd =56.0 of the first lens material; the refractive index Nd =1.64 and the Abbe number Vd =23.5 of the second lens material; the refractive index Nd =1.54 and Abbe number Vd =56.0 of the lens tri-material; the refractive index Nd =1.64 and the Abbe number Vd =23.5 of the four materials of the lens; the IR filter uses a glass material, and has a refractive index Nd =1.52 and an abbe number Vd =64.2.
The beneficial effects of the invention are:
compared with the prior art, the surface types of the four lenses are designed by adopting the aspheric surface type, the aspheric surface design freedom degree is high compared with the early traditional spherical surface type, and the total length and the focal length of the whole lens can be better shortened. In addition, the four lenses are all made of plastic materials, the density of the plastic materials is smaller than that of glass, the weight is lighter, in addition, the glass materials are generally only used for processing spherical lenses, the difficulty of processing the aspherical lenses is higher, the four lenses are manufactured through a mold injection molding process, the process is very convenient for processing the aspherical surfaces, and the miniaturization of the lens can be better realized. The small infrared thermal imaging lens with the total lens length TTL being less than or equal to 13.6mm, the focal length EFL being less than or equal to 7.2mm and the full FOV being less than or equal to 52.5 degrees has the advantages of good imaging quality, small and light structure, low cost and wide application range, improves the core competitiveness of related products, and improves the user experience.
Drawings
FIG. 1 is a schematic cross-sectional view of the present invention;
FIG. 2 is a cross-sectional view of a lens of the invention;
FIG. 3 is a second cross-sectional view of the lens of the present invention;
FIG. 4 is a three-section view of a lens of the invention;
FIG. 5 is a four-section view of a lens of the invention;
FIG. 6 is a schematic front view of the present invention;
FIG. 7 is a schematic of the optical path of the present invention;
in the figure: a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, an IR filter 5, a photosensitive element image side surface 6, a diaphragm 7 and a lens barrel 8.
Detailed Description
The invention will be further described with reference to the drawings and specific embodiments, which are provided herein for the purpose of illustrating the invention and are not to be construed as limiting the invention.
As shown in fig. 1-7: the invention comprises a lens cone 8, a photosensitive element image side surface 6, a lens I1, a lens II 2, a lens III 3 and a lens IV 4, wherein the photosensitive element image side surface 6 is arranged on one side of the image side surface of the lens cone 8, the lens I1, the lens II 2, the lens III 3 and the lens IV 4 are fixedly arranged in the lens cone 8 from the object side surface to the image side surface in sequence, a diaphragm 7 is arranged on the object side surface of the lens cone 8, the object side surface of the central axis of the lens I1 is a convex surface, the image side surface is a concave surface, the object side surface and the image side surface of the central axis of the lens II 2 are both concave surfaces, the object side surface of the central axis of the lens III 3 is a concave surface, the image side surface is a convex surface, the object side surface of the central axis of the lens IV 4 is a convex surface, and the image side surface is a concave surface;
the efficiency of the photosensitive element for receiving the image can be effectively increased by controlling the position of the diaphragm, and simultaneously, a sufficiently large field angle is ensured. The first lens, the second lens, the third lens, the fourth lens and the IR filter of the imaging lens group are provided with air gaps between any two adjacent elements, so that the total length TTL of the lens is convenient to adjust and aberration is convenient to correct. The first lens element with positive refractive power has a convex surface near the object-side surface (11) and a concave surface near the paraxial region (12), and can collect light rays to the maximum extent by controlling the refractive power of the first lens element, thereby facilitating correction of spherical aberration of the lens element and facilitating entry of large-field-angle light rays into the optical system. The second lens element with negative refractive power has a concave surface near the object-side surface (21) and a concave surface near the paraxial region, and the refractive power configuration of the second lens element is controlled to help correct the aberration of the optical system and improve the imaging quality of the lens system. The third lens element with positive refractive power has a concave surface near the object-side surface and near the optical axis, and has a concave surface near the image-side surface and near the optical axis, and at least one of the object-side surface and the image-side surface has a inflection point. The fourth lens element with negative refractive power has a convex side near the object side and a concave side near the image side, and the refractive power configuration of the fourth lens element is controlled to help correct the aberration of the optical lens assembly and improve the imaging quality of the lens. The four lenses all have two surfaces, the surface close to the object side surface is called an R1 surface, the surface close to the image side surface is called an R2 surface, and a thickness value exists between the two surfaces of each lens R1 and R2, and the central thickness value is called CT. The surface types of the four lenses are all aspheric surface types, the surface types have higher design freedom degree than the spherical surface types, more variables are provided, an optical system can be more conveniently optimized, aberration is reduced to the maximum degree, and imaging quality is improved.
Lens parameters for examples of the invention are given in the table below
The total lens length TTL from the lens barrel 8 to the image side surface 6 of the photosensitive element is less than or equal to 13.6mm, the focal length EFL is less than or equal to 7.2mm, and the total FOV is not less than 52.5 degrees.
Further, an IR filter 5 is disposed on an image side surface of the lens four 4, and the IR filter 5 is fixedly disposed in the lens barrel 8.
Preferably, the thickness of the air gap between the first lens 1 and the second lens 2 is 1.41mm; the thickness of the air gap between the second lens 2 and the third lens 3 is 0.45mm; the air gap thickness between the lens three 3 and the lens four 4 is 0.13mm; the air gap thickness between the lens four 4 and the IR filter 5 is 1.35mm; the air gap between the IR filter 5 and the image side 6 of the photosensitive element is 1.45mm.
Preferably, the first lens 1 outer diameter dimension D1= phi 8.8mm, the second lens 2 outer diameter dimension D2= phi 9.0mm, and the third lens 3 outer diameter dimension D3= phi 9.6mm; the lens four 4 outer diameter dimension D4= phi 10.0mm.
Preferably, the first lens thickness CT1=1.20mm, the second lens thickness CT2=1.00mm, the third lens thickness CT3=3.55mm, the fourth lens thickness CT4=0.80mm, and the IR filter 5 thickness dimension is 0.70mm.
Preferably, the first lens 1 side thickness dimension ET1=1.570mm, the second lens 2 side thickness dimension ET2=1.800mm, the third lens 3 side thickness dimension ET3=1.700mm, and the fourth lens 4 side thickness dimension ET4=1.310mm.
Preferably, the radius of curvature of the object side surface of the first lens 1 is 4.0mm, the aspheric diameter phi of the object side surface is 3.21mm, the radius of curvature of the image side surface is 21.5mm, and the aspheric diameter phi of the image side surface is 3.47mm; the radius of curvature of the object side surface of the second lens 2 is-18.4 mm, the diameter of the aspheric surface of the object side surface is phi 3.66mm, the radius of curvature of the image side surface is 6.2mm, and the diameter of the aspheric surface of the image side surface is phi 5.59mm; the radius of curvature of the object side of the third lens 3 is-27.5 mm, the diameter of the aspheric surface of the object side is phi 5.84mm, the radius of curvature of the image side is-1.8 mm, and the diameter of the aspheric surface of the image side is phi 6.84mm; the radius of curvature of the object side surface of the four 4 lens is 2.7mm, the diameter phi of the aspheric surface of the object side surface is 7.99mm, the radius of curvature of the image side surface is 1.35mm, and the diameter phi of the aspheric surface of the image side surface is 8.04mm.
Preferably, the diameter of the light-passing hole of the diaphragm 7 is 2.85mm.
Preferably, the first lens 1, the second lens 2, the third lens 3 and the fourth lens 4 are all made of plastic materials.
Preferably, the refractive index Nd =1.54 and the abbe number Vd =56.0 of the first lens material 1; the refractive index Nd =1.64 and the Abbe number Vd =23.5 of the second lens 2 material; the refractive index Nd =1.54 and Abbe number Vd =56.0 of the lens three 3 material; the refractive index Nd =1.64 and the Abbe number Vd =23.5 of the lens four 4 material; the IR filter 5 uses a glass material, and has a refractive index Nd =1.52 and an abbe number Vd =64.2.
The technical solution of the present invention is not limited to the limitations of the above specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the protection scope of the present invention.
Claims (2)
1. The utility model provides a short burnt lens of small-size infrared thermal imaging, includes lens cone (8) and photosensitive element looks like side (6), photosensitive element looks like side (6) set up in the looks like side one side of lens cone (8), its characterized in that: the small infrared thermal imaging short-focus lens is composed of a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4), wherein the first lens (1), the second lens (2), the third lens (3) and the fourth lens (4) are sequentially and fixedly arranged in the lens barrel (8) from an object side surface to an image side surface, the object side surface of the lens barrel (8) is provided with a diaphragm (7), the object side surface of the first lens (1) at the middle axis is a convex surface, the image side surface is a concave surface, the object side surface and the image side surface of the second lens (2) at the middle axis are concave surfaces, the object side surface of the third lens (3) at the middle axis is a convex surface, the object side surface of the fourth lens (4) at the middle axis is a convex surface, and the image side surface is a concave surface;
the total lens length TTL from the lens barrel (8) to the image side surface (6) of the photosensitive element is less than or equal to 13.6mm, the focal length EFL is less than or equal to 7.2mm, and the total FOV is not less than 52.5 degrees;
an IR filter (5) is arranged on the image side surface of the lens IV (4), and the IR filter (5) is fixedly arranged in a lens cone (8);
the refractive index Nd =1.54 and the Abbe number Vd =56.0 of the material of the first lens (1); the refractive index Nd =1.64 and Abbe number Vd =23.5 of the material of the second lens (2); the refractive index Nd =1.54 and Abbe number Vd =56.0 of the material of the third lens (3); the refractive index Nd =1.64 and Abbe number Vd =23.5 of the material of the lens four (4); the IR filter (5) is made of a glass material, and has a refractive index Nd =1.52 and an Abbe number Vd =64.2;
the air gap thickness between the first lens (1) and the second lens (2) is 1.41mm; the air gap thickness between the second lens (2) and the third lens (3) is 0.45mm; the air gap thickness between the lens three (3) and the lens four (4) is 0.13mm; the air gap thickness between the lens four (4) and the IR filter (5) is 1.35mm; the air gap between the IR filter (5) and the image side surface (6) of the photosensitive element is 1.45mm;
the first lens (1) outer diameter dimension (D1) phi =8.8mm, the second lens (2) outer diameter dimension (D2) phi =9.0mm, and the third lens (3) outer diameter dimension (D3) phi =9.6mm; the lens has a four (4) outer diameter dimension (D4) phi =10.0mm;
the lens one (1) thickness (CT 1) =1.20mm, the lens two (2) thickness (CT 2) =1.00mm, the lens three (3) thickness (CT 3) =3.55mm, the lens four (4) thickness (CT 4) =0.80mm, the IR filter (5) thickness dimension is 0.70mm;
the first lens (1) side thickness dimension (ET 1) =1.570mm, the second lens (2) side thickness dimension (ET 2) =1.800mm, the third lens (3) side thickness dimension (ET 3) =1.700mm, and the fourth lens (4) side thickness dimension (ET 4) =1.310mm;
the radius of curvature of the object side surface of the first lens (1) is 4.0mm, the diameter phi of an aspheric surface of the object side surface is 3.21mm, the radius of curvature of an image side surface is 21.5mm, and the diameter phi of the aspheric surface of the image side surface is 3.47mm; the radius of curvature of the object side surface of the second lens (2) is-18.4 mm, the diameter phi of the aspheric surface of the object side surface is 3.66mm, the radius of curvature of the image side surface is 6.2mm, and the diameter phi of the aspheric surface of the image side surface is 5.59mm; the radius of curvature of the object side surface of the lens III (3) is-27.5 mm, the diameter of an aspheric surface of the object side surface is phi 5.84mm, the radius of curvature of the image side surface is-1.8 mm, and the diameter of the aspheric surface of the image side surface is phi 6.84mm; the radius of curvature of the object side surface of the lens four (4) is 2.7mm, the diameter phi of the aspheric surface of the object side surface is 7.99mm, the radius of curvature of the image side surface is 1.35mm, and the diameter phi of the aspheric surface of the image side surface is 8.04mm;
the diameter of a light through hole of the diaphragm (7) is 2.85mm.
2. The compact infrared thermal imaging short-focus lens of claim 1, wherein: the first lens (1), the second lens (2), the third lens (3) and the fourth lens (4) are all made of plastic materials.
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| CN112526723A (en) * | 2020-12-18 | 2021-03-19 | 辽宁中蓝光电科技有限公司 | TOF lens using free-form surface |
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| US9864168B2 (en) * | 2014-06-23 | 2018-01-09 | Genius Electronic Optical Co., Ltd. | Near-infrared lens for cameras in mobile devices |
| CN111983777B (en) * | 2019-05-21 | 2022-09-20 | 新巨科技股份有限公司 | Four-piece type dual-waveband imaging lens group |
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| CN112526723A (en) * | 2020-12-18 | 2021-03-19 | 辽宁中蓝光电科技有限公司 | TOF lens using free-form surface |
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Denomination of invention: A Small Infrared Thermal Imaging Short Focus Lens Effective date of registration: 20230925 Granted publication date: 20221213 Pledgee: Bank of Beijing Limited by Share Ltd. Shenzhen branch Pledgor: SHENZHEN DULE PRECISION MANUFACTURING CO.,LTD. Registration number: Y2023980058731 |
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